Py. Scarabin et al., CHANGES IN HEMOSTATIC VARIABLES INDUCED BY ORAL-CONTRACEPTIVES CONTAINING 50 MU-G OR 30 MU-G ESTROGEN - ABSENCE OF DOSE-DEPENDENT EFFECT ONPAI-1 ACTIVITY, Thrombosis and haemostasis, 74(3), 1995, pp. 928-932
Several studies have suggested a dose-response relation between the oe
strogen content of oral contraceptive (OC) and the risk of both venous
thrombosis and arterial disease, when oestrogen doses were higher tha
n 50 mu g However, there is no clear epidemiological evidence for a de
crease in thrombotic risk with formulations containing less than 50 mu
g oestrogen. Therefore, we investigated haemostatic variables in user
s of OC containing either 30 mu g (35 women) or 50 mu g (29 women) eth
inyl estradiol as compared with non users (64 women) matched for age a
nd smoking status. Mean values of antithrombin activity were significa
ntly lower in 30 mu g or 50 mu g oestrogen users than in non users (96
% and 98% vs 105%, respectively, p<0.001), but they were not significa
ntly different between the two groups of OC users. There was a signifi
cant increase in mean values of factor VII antigen in women taking eit
her 30 mu g or 50 mu g oestrogen as compared with non users (96% and 1
01% vs 85%, respectively, p<0.005). Although the difference between bo
th groups of OC users was not significant, a positive linear trend in
factor VII levels was observed within the 0-50 mu g oestrogen range (p
<0.001). Mean levels of fibrinogen were slightly higher in 30 mu g or
50 mu g oestrogen users than in non users (2.71, 2.66 g/l vs 2.55 g/l,
respectively,), but there was no significant difference between the t
hree groups. Mean values of PAI-1 activity were significantly lower in
both groups of OC users than in non users (4.89 and 4.63 AU/ml vs 6.4
7 AU/ml, respectively, p<0.02), but this decrease was not dose-depende
nt. There was no significant difference in haemostatic variables betwe
en 30 mu g oestrogen preparations containing either 100 mu g (13 women
), 150 mu g (3 women) or 200 mu g (19 women) levonorgestrel. In 50 mu
g oestrogen preparations, the wide range of different types of progest
ogens did not allow valid assessment of progestogens effect. These dat
a provide further evidence for an alteration of blood coagulation and
fibrinolysis in OC users within the 30 mu g-50 mu g oestrogen range. H
owever, despite a possible dose-dependent effect of oestrogen on facto
r VII? our results suggest no substantial change in PAI-1 activity and
other markers of thrombogenic risk when oestrogen content of combined
OC is decreased from 50 mu g to 30 mu g. The potential role of proges
togens in haemostatic system needs further investigations.